Lex glycosphingolipids-mediated cell aggregation.
Glycoconjugates bearing oligosaccharide Lex, Galbeta1-->4(Fucalpha1-->3)GlcNAcbeta1-->3R, are found on the surface of several cell types. Although recent studies have indicated that Lexon both glycosphingolipids (GSL) and polylactosaminoglycans can mediate under certain experimental conditions Lex-Lexinteractions, cell-cell interactions based exclusively on LexGSLs have not been demonstrated. In this study we show that preincubation of nonaggregating rat basophilic leukemia (RBL) cells with purified LexGSLs resulted in incorporation of the GSLs into plasma membrane, as determined by immunostaining, and formation of aggregates in the presence of Ca2+; no aggregates were formed after preincubation of the cells with globoside or sphingomyelin. Lex-mediated aggregation was inhibited by removal of Ca2+or by addition of lactofucopentaose III but not by lactose or lacto-N-fucopentaose II. In a mixture of Lex-positive and Lex-negative RBL cells most of the aggregates were composed exclusively of Lex-positive cells. The combined data suggest that interactions between LexGSL on opposite cell surfaces are strong enough to allow formation of stable cell-cell contacts.
Boubelík
M
M
Department of Mammalian Gene Expression, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague.
Floryk
D
D
Bohata
J
J
Dráberová
L
L
Macák
J
J
Smíd
F
F
Dráber
P
P
D000818:Animals; D006528:Carcinoma, Hepatocellular; D002448:Cell Adhesion / Q000187:drug effects; D002449:Cell Aggregation / Q000187:drug effects; D003110:Colonic Neoplasms; D006028:Glycosphingolipids / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D015471:Leukemia, Basophilic, Acute; D007983:Lewis Blood Group Antigens / Q000502:physiology*; D008113:Liver Neoplasms; D009844:Oligosaccharides / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D000080506:Sialyl Lewis X Antigen; D014407:Tumor Cells, Cultured
D006028:Glycosphingolipids; D007983:Lewis Blood Group Antigens; D009844:Oligosaccharides; D000080506:Sialyl Lewis X Antigen